In many industrial, scientific and other applications, it is necessary to perform insertion operations, such as putting pegs in holes, screws into threaded apertures, placing parts into specific locations, and similar operations. Conventionally, such operations could be done by hand by humans, but this work is tedious and boring, and often requires extremely precise and delicate placement which may not be possible for humans to accomplish for extended periods of time or with the proper delicacy. In addition, the use of human labor is often extremely expensive. Mechanical hands and arms using servo and force sensors have been used in many applications. These devices are typically extremely expensive because of the complex circuitry required to sense and feed back operational signals to the servos, and because of the relatively high cost of the computers and software which must be used to operate such systems. More recently, a variation on these mechanical devices has been introduced which searches in one dimension for a periphery and then returns some predetermined distance to an assumed middle point and then performs the same operation in a perpendicular direction. This too is a relatively expensive and complex device. Proximate center mechanical centering devices have been suggested for such applications, but they necessarily require the presence of part of their supporting structure in the work area, where it may interfere with the operations of the device.
While human operators are limited as to the size and force of the tasks they can perform, the automated devices are not so limited but they do require increasing energy with increasing size and force range demands.